1. Field of the Invention
Embodiments of the invention relate to the field of nanotechnology, and more specifically, to carbon nanotubes.
2. Description of Related Art
Carbon nanotubes (CNTs) are promising elements in nanotechnology. They are fullerene-related structures which consist of graphene cylinders. Applications that may be benefited using carbon nanotubes include high thermal conductivity materials for future packaging thermal demands. The solders used in interconnect between the silicon (Si) die and the substrate have inherently lower resistance to electro-migration primarily due to their electrical resistivity and lower strength or modulus.
Typical solder has a critical product of electro-migration value approximately 102 times lower than copper (Cu), which is used in metallization in silicon die. The critical current density beyond which electro-migration may become a problem is approximately 106 A/cm2 for Cu. Therefore, the critical current density beyond which electro-migration may become a problem is approximately 104 A/cm2 for solder because it is 102 times lower than Cu. In other words, the existing solder may face serious electro-migration risk when the current density reaches approximately 104 A/cm2. This current density is being approached by existing technology. Presently, the solder electro-migration is driven by the interfacial reaction and/or defect (e.g., void or trapped filler) not necessarily by the inherent electro-migration in the solder. Although the electro-migration issues may be addressed by other techniques, the solder soon faces electro-migration risk because it starts to be subject to intensive electro-migration damage at current densities around or greater than 104 A/cm2.